1997 Volume 25 Issue 4 Pages 239-241
Rodlike and semiflexible polymers, most of which are capable of forming lyotropic liquid crystals at high concentrations, are referred to as non-flexible polymers. They show some remarkable differences in dynamic properties from flexible polymers, e. g., remarkable concentration and molecular weight dependences of viscosity; no simple power law exists. This paper presents our recent effort toward slow global dynamics such as diffusion and viscosity mainly from theoretical aspects. Indeed new theories are developed, where a new model, the fuzzy cylinder model, has been introduced to replace the wormlike cylinder to derive expressions for diffusion and viscosity, which contain only one adjustable parameter, the similitude ratio λ*. When both entanglement and hydrodynamic interacations are considered, they are used successfully to data for non-flexible polymers with the persistence length q in the range between 10 and 200 nm, but limited to Kuhn statistical segment number below 20. However the theory is not satisfactory for dielectric dispersions, which contain intramolecular motional modes neglected in the above theoretical development.
